Use of tris(hydroxymethyl) aminomethane in cold permanent waving processes

ABSTRACT

There is provided a hair treatment composition for cold permanent hair waving. The composition is a lotion, preferably in the form of an aqueous solution, having a pH in the range of from about 6 to less than 8.5 and a viscosity in the range of from 1 to about 3000 cps and contains tris(hydroxymethyl)amino methane and a reducing agent.

RELATED APPLICATION

[0001] This application is a continuation-in-part of my co-pendingapplication Ser. No. 09/708,157, filed Nov. 7, 2000.

FIELD OF THE INVENTION

[0002] The present invention relates to compositions used in permanenthair waving processes. More particularly, the present invention relatesto hair treatment compositions that improve the styling and reshaping ofhair using a cold permanent hair waving process.

BACKGROUND TO THE INVENTION

[0003] Hair is made up of a fibrous protein called keratin. The shapeand stability of the structure of this protein is provided by threeinteractions; (1) covalent bonding of cystine cross-linkages; (2)hydrogen bonding; and (3) salt linkages. The disulfide bonds in cystineare the strongest of these stabilizing forces.

[0004] To change the natural shape of hair, various treatments have beendevised. One such treatment is permanent waving of hair, which can beused to either increase or decrease the amount of curl in hair.Permanent waving of hair may be performed using different types oftreatments. One such treatment is heat waving, which facilitates thebreakage of the disulfide bonds by applying heat in conjunction withalkali, or a combination of an alkali and a sulfite reducing agent.However, the heat treatment and chemicals involved tend to weaken thehair fibers and most of the reactions are irreversible. EP 129807describes a heat waving process in which an amino acid free of amercapto group is used in conjunction with an alkali, e.g.,tris(hydroxymethyl) amino methane. According to EP '807 a reducing agentis not used in the disclosed heat waving process.

[0005] The heat waving method for permanent waving of hair has beenreplaced by the popular cold waving process, which restores thedisulfide bonds as herein described. This technique for permanent wavinguses chemical compounds that are capable of breaking the disulfide bondsand reshaping the hair without the provision of heat.

[0006] In cold waving, permanent waving is accomplished by a processthat requires (a) chemically cleaving the disulfide bonds in hair with areducing agent, (b) optionally rinsing the hair after cleaving thedisulfide bonds, and (c) forming new disulfide bonds with an oxidizingagent while the hair is under tension in the new shape that is desired.The cold waving process is gentler to the hair than the heat wavingprocess because the initial damage to the hair is largely reversible.

[0007] A lasting permanent wave can be achieved when the disulfide bondsare arranged in a new configuration. To reshape the hair, it is believedthat 20% to 60% of the disulfide bonds must be broken and reconfiguredin the new shape.

[0008] As stated previously, the reducing agent is used to break thedisulfide bonds. Selection of a reducing agent is largely dependent uponthe pH of the permanent cold waving composition. Generally, acidic coldpermanent wave compositions employ reducing agents, such as glycerolmonothioglycolate or bisulfates, and work in the lower pH range. On theother hand, cold alkaline permanent wave compositions utilize alkalinesalts of thioglycolic acid. The reducing agent penetrates and swells thehair shaft thus enabling the disulfide bonds to be broken. In the coldwaving process, a thiol compound, also known as a mercaptan, istypically used as the reducing agent.

[0009] Traditionally, ammonia and monoethanolamine have been used asalkalizers. However, there are drawbacks associated with thesecompounds. Ammonia performs well, but has a strong, irritating odor,which makes it unpleasant. Monoethanolamine has less of an odor and iscommonly used as a substitute for ammonia. However, its pKa value is9.50. This means that in a composition having a pH of 7.5, there is onlyone percent free amine. Thus, monoethanolamine is not as effective insuch a composition. In the practice of cold waving, low heat issometimes applied while the reducing agent is present on the hair. Thisaccelerates the rate of cleaving of the disulfide bonds. When low heatis used, temperatures are generally less than about 50° C. during thisstep, usually below 30° C., but greater than room temperature.

[0010] One drawback to cold waving is the actual permanence of thechange in shape of the hair. The newly configured hair tends to lose itsshape when subject to normal stresses such as brushing, shampooing, anddrying of the hair. These normal wear and tear stresses weaken the newdisulfide bonds, which are constantly placed under tension.

[0011] Another drawback is the efficiency of the permanent wave.Efficiency has been characterized in the art as the tightness of thecurl or “true to rod size.” Although ammonia is effective at low pH, ithas a strong harsh odor. Monoethanolamine can be used as a substitute,which has a more acceptable odor, but is less efficient at low pH.

SUMMARY OF THE INVENTION

[0012] It is an object of the present invention to provide a hairtreatment composition that increases the longevity of a cold permanentwave.

[0013] It is another object of the present invention to provide such ahair treatment composition that increases the efficiency of a coldpermanent wave.

[0014] It is also an object of the present invention to provide such ahair treatment composition that has a pH from about 6 to less than 8.5.

[0015] It is another object of the present invention to provide a hairtreatment composition that has a high percentage of free amine in the pHrange of from about 6.5 to about 8.0, preferably in the pH range of fromabout 7.0 to 8.0, more preferably in the pH range of 7.5 to 8.0.

[0016] It is still another object of the present invention to providesuch a hair treatment composition that exhibits an acceptable odor.

[0017] These objects and advantages are achieved by the presentinvention, which is a hair treatment composition for cold permanent hairwaving comprising tris(hydroxymethyl)aminomethane and a reducing agent.

DETAILED DESCRIPTION OF THE INVENTION

[0018] An essential component in the present hair treatment compositionfor cold permanent waving is tris(hydroxymethyl)amino methane (“Tris”),also known as tromethane. Tris serves as an alkalizer in the presentcomposition. This compound has the structure shown in formula (I):

[0019] Tris is present in an amount from about 0.2 percentage by weightor weight percent (wt. %) to about 10 wt. % of the total weight of thepresent permanent waving composition. Cost considerations make levelsabove 10 wt. % undesirable. Preferably, Tris is present in an amountfrom about 0.5 wt. % to about 5 wt. % of the present composition.

[0020] The pKa of Tris is about 8.06. At a pH of about 7.5. Tris hasabout 22% free amine, which is significantly greater thanmonoethanolamine. In fact, monoethanolamine has only 1% free amineavailable at the same pH. This is a critical point because a higherpercentage of free amine (a) increases the diffusion of the amine intothe hair and provides a greater number of reactive sites for thereaction between the amine and the reducing agent, and (b) provides abetter buffering system to hold the pH at the desired level.

[0021] The second essential component of the present hair treatmentcomposition for cold permanent waving is a reducing agent. Any suitablereducing agent can be used. Such suitable reducing agents include, butare not limited to thiols (mercaptans), inorganic sulfides, sulfites,hydrosulfites, phosphines, cyanides, and combinations thereof. Thepreferred reducing agent is a thiol or sulfite compound.

[0022] In general, any suitable thiol compound that can be used in apermanent waving composition may be employed. Preferred thiols include,but are not limited to, glycerol monothioglycolate, cysteamine,thioglycolic acid and salts of thioglycolate acid, ammoniumthioglycolate, monoethanolamine thioglycolate, cysteine thioglycolate,cysteine, thiolactic acid and its salts, iso-octyl thioglycolate,N-acetyl-L-cysteine, and combinations thereof.

[0023] The pKa of a particular reducing agent is important because itgreatly affects the rate at which chemical equilibrium of the reducingreaction is reached. In the present composition, the pKa of the reducingagent is about 6 to about 10. Preferably, the pKa is about 6.5 to about9.5, more preferably about 7 to about 9.

[0024] The reducing agent is present in the present composition in anamount from about 2 wt. % to about 30 wt. % of the total composition.Preferably, the reducing agent is about 5 wt. % to about 20 wt. % of thetotal weight of the permanent wave composition. More preferably, thereis about 8 wt. % to about 15 wt. % of the reducing agent in the presentcomposition. The actual amount of the reducing agent that is included isdetermined by the waving efficiency desired.

[0025] The present composition may also have other components oradditives. The additives may include, for example, one or more swellingagents such as urea, diammonium dithiodiglycolate, other alkalizers,chelating agents, fragrances, dyes, opacifiers, pearlescing agents,thickeners, wetting and foaming agents, foam stabilizers, preservatives,softening agents, surfactants, acids, buffers, solvents, conditioners,and mixtures thereof.

[0026] Suitable materials for these purposes are identified in theInternational Cosmetic Ingredient Dictionary and Handbook (published byThe Cosmetic, Toiletry and Fragrance Association)(Eighth Edition 2000).These materials may be included in the composition at concentrationseffective to provide their intended function as commonly known in theart.

[0027] By including diammonium dithioglycolate in the permanent wavingcomposition of the present invention, greater flexibility in processingtime is gained, because it minimizes the possibility of overprocessing.That is, diammonium dithioglycolate forms an equilibrium reaction withthe thiol reducing agent and with cysteine in the hair keratin, whichproceeds to a certain point and thus minimizes the possibility ofoverprocessing the hair.

[0028] Examples of other alkalizers include, but are not limited to,ammonium hydroxide, ammonium carbonate, ammonium bicarbonate, ammoniumchloride, monoethanolamine, and combinations thereof.

[0029] Chelating agents that bind metal ions in solution may be includedin the present composition. Examples of these chelating agents areethylene diamine tetraacetic acid (EDTA) and its derivatives such astetrasodium EDTA, and 1-hydroxyethylene-(1,1 diphosphonic acid) soldunder the tradename Dequest 2010® by Solutia.

[0030] Wetting and foaming agents can also be included in thecomposition to improve penetration of the composition into the hairthereby enhancing thiol diffusion. Examples include, but are not limitedto conditioners such as quaternized fatty amines or silicones.

[0031] Opacifiers can be included in the composition to provide a milkyappearance. Emulsions of acrylic, vinyl, and styrene polymers andcopolymers are some examples of opacifiers that are suitable.

[0032] In a preferred embodiment, the hair treatment composition has anamount from about 0.2 wt. % to about 5 wt. % tris(hydroxymethyl)aminomethane and from about 8 wt. % to about 15 wt. % of a thiol compound.The pH of this preferred composition is about 6.5 to about 9.5.Preferably, the pH is about 7.0 to less than 8.5. More preferably, thepH is about 7.5 to about 8.0.

[0033] Optionally, tris(hydroxymethyl)amino methane may be combined withammonia, monoethanolamine, or combinations thereof.

[0034] The present invention includes a cold permanent waving processcomprising the steps of (a) applying to hair a permanent wavingcomposition comprising tris(hydroxymethyl)amino methane and a reducingagent, (b) allowing the permanent waving composition to set for asufficient time, (c) removing the permanent waving composition from thehair, and (d) applying a restoring agent selected from the groupconsisting of oxidizing agents, crosslinking agents, and mixturesthereof to the hair. Optionally, the cold waving process may furthercomprise step (e) shaping the hair, prior to step (a) or after steps (b)or (c). Preferably, removing step (c) is performed by rinsing withwater. Optionally, low heat may be applied during step (b), e.g., heatedair at a temperature generally less than 50° C., usually less than below30° C.

[0035] The cold permanent waving compositions of this invention are inthe form of a lotion, generally as an aqueous solution, having aviscosity in the range of from 1 to 3000 centpoises (cps), preferablywithin the range of from 5 to about 2000 cps, more preferably within therange of from 5 to about 500 cps.

[0036] In the cold permanent waving process, the permanent wavingcomposition is applied as a lotion, after the hair has been shampooed.The hair may be reconfigured into its new shape prior to or afterapplying the permanent waving composition. Next, the permanent wavingcomposition is allowed to remain on the hair for a sufficient amount oftime to break a sufficient number of disulfide bonds. This may require 1minute to 60 minutes of contact time, typically from about 10 to about30 minutes. Low heat, e.g., from a hood style dryer, may be applied ifnecessary and as described previously. The permanent wave composition isthen removed from the hair. Generally, this entails thoroughly rinsingthe hair with water. Then, the disulfide bonds are restored. This stepis essential to increase the tensile strength of the hair. Oxidizingagents typically employed include, but are not limited to, hydrogenperoxide and bromates. Crosslinking agents that are suitable include,but are not limited to alkylene dihalides, dihalocarboxylic acids,dimaleimides, and the like.

[0037] To illustrate the present invention, the following examples areprovided. However, it should be understood that the present invention isnot limited to the examples described.

EXAMPLES

[0038] Three waving lotions were tested using aqueous solutions having13.2 wt. % (0.8M) glyceryl monothioglycolate (GMT) and variousconcentrations of an amine alkalizer (ammonia, monoethanolamine, orTris) as shown in Tables 1 and 2. The pH was adjusted using a 10 wt. %HCl solution. Tresses were rolled onto mandrels and evaluated using thepermanent wave evaluation procedure that follows.

[0039] Procedure for Permanent Wave Evaluation

[0040] Each tress evaluation was conducted in quadruplicate to provide ameasurement with a standard deviation of approximately 10%.

[0041] 1. A bundle of 16 inch long medium virgin brown hair was securedwith beeswax by dipping approximately 2 inches of the root end of thebundled hair into melted wax for 5 seconds. When the wax is cool to thetouch, it is shaped into a square and allowed to harden.

[0042] 2. Hair is broken into smaller bundles, washed with a 10 wt. %sodium lauryl sulfate solution and then rinsed.

[0043] 3. Hair is sectioned into tresses of 45 hairs and the waxed endis re-waxed to further secure the tress. The wax is allowed to dry, anda piece of tape is wrapped around it to provide a writing surface.Tresses are trimmed to a length of 12 inches (30 cm) from the bottomedge of the tape.

[0044] 4. An 8 cm long, 1.25 cm diameter spiral rod with 25 turns isused. The waxed end of the hair is secured between the gth and ₁₀thturns using a rubber band. The tress and rod are then soaked in a 0.1wt. % solution of Triton X-100 (a mixture ofoctylphenoxypolyethoxyethanol and polyethylene glycol) for approximately3 minutes.

[0045] 5. A piece of tape, width 2.5 cm, is wrapped sideways around thebottom edge of the hair, covering the bottom 2.5 cm. A 3.4 g alligatorclip is used to secure the tape. Using a piece of copper wire as a hook,a 6 oz. weight is hung from the tape at the bottom of the hair. The hairis rolled around the rod, using the weight to provide equal tensionduring rolling. The weight is removed after rolling, and the bottom tapeis secured around the rod with a piece of Tygon tubing.

[0046] 6. The rod is placed in a wide mouth test tube that contains 10mL of the appropriate waving lotion, i.e. the composition of Examples 1,2, 3 or 4. The solution completely covers the hair. The test tube isplaced in a constant temperature water bath at 37° C. for 20 minutes.

[0047] 7. The rod is removed and rinsed for 3 minutes under running tapwater at approximately 30° C. and a flow rate of approximately 1liter/minute. The rod is then placed into a new test tube with 10 mL ofneutralizer (2 wt. % hydrogen peroxide, 0.05 wt. % polyquat-11, andphosphoric acid to pH 3.1). The rod is removed and rinsed with the 30°C. tap water for 2 minutes.

[0048] 8. The tress is soaked in a bowl of 30° C. tap water for 5minutes to allow complete oxidation. The tress is then carefullyunrolled from the rod without tension, starting from the bottom andkeeping the spiral configuration intact. The tape is cut off the hairusing scissors while the hair is still on the rod.

[0049] 9. The tress is hung by the top piece of tape and allowed to drywhile hanging for 1 hour.

[0050] 10. The tress is then hung in a glass containerfilled with a 0.1%Triton X-100 solution (by weight). A glass container (10×11.5×4 in) isused in which clear plastic rulers are glued along the front and backwalls. A copper wire is secured across the top of the container. Therulers should be lined up to provide a way to accurately measure thehair. A copper wire hook is placed through the tape at the top of thetress and hung on the wire. The tress is soaked for 1 hour and thenmeasured using the rulers in the water.

[0051] Waving Efficiency

[0052] After the procedure, the lengths of the tresses were measured ina water bath. The shorter the tress, the tighter the curl and the betterthe product. The curl is measured from the end of the wax to the end ofthe curl.${{Wave}\quad {efficiency}} = {\frac{L_{i} - L_{t}}{L_{i} - L_{o}} \times 100}$

[0053] where

[0054] L_(i)=initial length of tress from wax end to tip,

[0055] L_(o)=length of tress when wrapped on the rod, and

[0056] L_(t)=length of permed hair from wax end to tip, measured in thewater

[0057] Tables 1 and 2 show that Tris is an effective alkalizer for a lowpH waving lotion. TABLE 1 Use of Various Amines (0.75 M) with GMT at pH7.5 Tress Length (cm) Percent Waving Amine L_(t) Efficiency Ammonia 15.5± 1.2 47.8 Monoethanolamine 16.1 ± 0.5 45.4 Tris 15.7 ± 0.9 47.0

[0058] TABLE 2 Use of Various Amines with GMT at pH 8.0 Molar TressLength Percent Concentration (cm) Waving Amine of Amine L_(t) EfficiencyAmmonia 0.4 14.5 ± 1.8 51.8 Ammonia 0.75 14.2 ± 0.6 53.0Monoethanolamine 0.4 15.7 ± 1.9 47.0 Monoethanolamine 0.75 17.6 ± 1.139.4 Tris 0.2 16.2 ± 0.9 45.0 Tris 0.4 14.8 ± 0.9 50.6 Tris 0.6 16.9 ±0.4 42.2 Tris 0.75 16.5 ± 1.4 43.8

[0059] Conclusions

[0060] Tris in combination with a reducing agent produces better resultsthan monoethanolamine with a reducing agent.

[0061] Use of Tris is beneficial in the pH range of about 6 to about 10using any thiol reducing agent. Better results are obtained at a pH ofabout 6.5 to about 9.5 and optimal results at a pH of about 7.5 to about8.5. This invention is useful for preparing formulations without ammoniaor in combination with ammonia, monoethanolamine, or mixtures thereof.Examples of thiols that are useful with this invention are glycerolmonothioglycolate, cysteamine, thioglycolic acid, cysteine,dithiothreitol, dithioerythritol and thiolactic acid.

[0062] Having thus described the present invention with particularreference to preferred embodiments thereof, it will be apparent thatvarious changes and modifications may be made therein without departingfrom the spirit and scope of the present invention as defined in theappended claims.

What is claimed is:
 1. A cold permanent hair waving compositioncomprising a lotion comprising: (a) from about 0.2 wt. % to about 10 wt.% tris(hydroxymethyl)amino methane; and (b) from about 2 wt. % to about30 wt. % of a reducing agent selected from the group consisting of asulfite compound and a thiol compound, and (c) an additive selected fromthe group consisting of one or more of swelling agents, diammoniumdithiodiglycolate, other alkalizers, chelating agents, fragrances, dyes,opacifiers, pearlescing agents, thickeners, wetting and foaming agents,foam stabilizers, preservatives, softening agents, acids, buffers,solvents, conditioners and mixtures thereof, and wherein the pH of saidcomposition is in the range of from about 6.0 to less than 8.5, theviscosity of the lotion is within the range of from 1 to about 3000centipoises (cps), and the weight percent are based on the total weightof the composition.
 2. The composition of claim 1, wherein saidcomposition has a pH of about 6.5 to about 8.0.
 3. The composition ofclaim 2, wherein said composition has a pH of about 7.5 to about 8.0. 4.The composition of claim 1, wherein said tris(hydroxymethyl)aminomethane is present in an amount from about 0.2 wt. % to about 10 wt. %of the total weight of the composition.
 5. The composition of claim 1,wherein the reducing agent is a thiol compound present in an amount offrom about 5 wt. % to about 15 wt. %, and is selected from the groupconsisting of glycerol monothioglycolate, cysteamine, thioglycolic acidand salts of thioglycolate acid, ammonium thioglycolate,monoethanolamine thioglycolate, cysteine thioglycolate, cysteine,thiolactic acid and salts of thiolactic acid, iso-octyl thioglycolate,N-acetyl-L-cysteine, and mixtures thereof.
 6. The composition of claim3, wherein the reducing agent is a thiol compound present in an amountof from about 5 wt. % to about 15 wt. %, and is selected from the groupconsisting of glycerol monothioglycolate, cysteamine, thioglycolic acidand salts of thioglycolate acid, ammonium thioglycolate,monoethanolamine thioglycolate, cysteine thioglycolate, cysteine,thiolactic acid and salts of thiolactic acid, iso-octyl thioglycolate,N-acetyl-L-cysteine, and mixtures thereof.
 7. The composition of claim1, wherein the reducing agent is a thiol compound.
 8. The composition ofclaim 3, wherein the reducing agent is a thiol compound.
 9. Thecomposition of claim 1, wherein the tris(hydroxymethyl)amino methane ispresent in an amount of up to about 5 wt. % of the total weight of thecomposition.
 10. The composition of claim 3, wherein thetris(hydroxymethyl)amino methane is present in an amount of up to about5 wt. % of the total weight of the composition.
 11. The composition ofclaim 1, wherein component (c) is diammonium thioglycolate.
 12. Thecomposition of claim 3, wherein Component (c) is diammoniumthioglycolate.
 13. The composition of claim 1, wherein the lotion has aviscosity within the range of from about 5 to about 2000 cps.
 14. Thecomposition of claim 3, wherein the lotion has a viscosity within therange of from 5 to about 2000 cps.
 15. The composition of claim 6,wherein the lotion has a viscosity within the range of from 5 to about2000 cps.
 16. The composition of claim 3, wherein saidtris(hydroxymethyl)amino methane is present in an amount from about 0.5wt. % to about 5 wt. % of the total weight of the composition.
 17. Thecomposition of claim 1, wherein said reducing agent has a pKa of about 6to about
 10. 18. The composition of claim 1, wherein said reducing agentis present in an amount up to about 20 wt. % of the total weight of thecomposition.
 19. The composition of claim 1, wherein the compositioncontains at least one other alkalizer and said other alkalizer isselected from the group consisting of: ammonium hydroxide, ammoniumcarbonate, ammonium bicarbonate, ammonium chloride, monoethanolamine,and mixtures thereof.
 20. The composition of claim 1, wherein thecomposition contains a chelating agent and said chelating agent isselected from the group consisting of ethylene diamine tetraacetic acidand derivatives thereof.